A south-facing roof in Cardiff generates about 1,029 kWh per kWp a year on the EU's PVGIS model, and every unit you use saves 26.55p at the Southern Wales price cap rate. A typical 4.5kWp system would make about 4,630 kWh a year, about 129 kWh per kWp in June against 33 kWh in December.
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A south-facing 1kWp system at 35 degrees in central Cardiff generates about 1,029 kWh a year, according to the EU's PVGIS model. That ranks 8 of the 20 areas we cover, which run from 850 kWh in Glasgow to 1,119 kWh in Dorset. East and west roofs still work, at roughly a fifth less.
| Roof direction (35° pitch) | Per kWp a year | June | December |
|---|---|---|---|
| South-facing | 1,029 kWh | 129 kWh | 33 kWh |
| East-facing | 796 kWh | 118 kWh | 14 kWh |
| West-facing | 822 kWh | 121 kWh | 15 kWh |
PVGIS is a modelled figure for an unshaded roof with 14% system losses, and it runs higher than the MCS method installers must use for your written estimate, which gives roughly 800 to 950 kWh per kWp for a well-oriented UK roof. Use PVGIS to compare places and the installer's MCS estimate to plan your budget. Our guides to which direction panels should face and how much electricity solar panels produce go further.
What that electricity is worth in Cardiff
Every unit you use yourself saves 26.55p, the Ofgem price cap rate for direct debit customers in the Southern Wales region from 1 October to 31 December 2026. The Great Britain average is 26.32p. Every unit you export earns whatever your Smart Export Guarantee tariff pays, which the Energy Saving Trust puts at around 12p typically.
Take the Energy Saving Trust's typical 4.5kWp home system. On the PVGIS figure for Cardiff it would generate about 4,630 kWh a year. If you used all of it, that would be worth about £1,229. If you exported all of it, about £556. Real homes sit between the two, and a battery or daytime use pushes you towards the higher figure. The Energy Saving Trust prices that typical system at around £7,600. See our solar panel cost guide and current export rates.
Two Welsh funding routes, and neither exists in England
Green Homes Wales lends owner-occupiers £1,000 to £25,000 interest free over up to 10 years for solar PV, and unlike almost every other home energy scheme in the UK it applies no means test. It is a Welsh Government scheme run by the Development Bank of Wales. Solar PV, solar PV with battery storage and solar PV with a diverter are all on the eligible measures list. Your home must be in Wales, owned by you and your main residence, and it must not be a new build or a listed building. Applications are subject to credit and affordability checks, the pot is first come first served, and the Welsh Government added more than £5 million to it for 2026-27.
If your income is low, Warm Homes Nest can fit solar panels for free instead. You must own or privately rent (council and housing association homes are excluded), you must either get a means-tested benefit or fall under the low-income threshold for your household type, and your home needs an EPC rating of 54 (E) or less, or 68 (D) or less if someone in the household has an eligible health condition. Cardiff Council also runs Tai Clyd Caerdydd with the Welsh Government, an area scheme for privately owned homes in Splott, Adamsdown and Fairwater that covers free advice, a home assessment and help finding vetted contractors. Our guide to solar panel grants in the UK covers the schemes that run across all four nations.
Welsh planning rules are not the English ones
In Wales, rooftop panels on a house are usually permitted development provided they sit no higher than the ridgeline and project no more than 200mm from the roof or wall surface. That 200mm figure is the Welsh Government's own, and the rule as written covers houses. If you live in a flat, the Welsh Government advises contacting the local planning authority before you commit to anything, because the permitted development right does not extend to you the way it does in Scotland. Panels on a flat roof cannot sit within 1 metre of the roof's external edge or stand more than 1 metre above the roof plane.
In a Cardiff conservation area or a World Heritage Site, planning consent is required for panels fitted to principal or side elevation walls that are visible from the highway. Roof slopes are treated differently from those walls. A listed building needs planning permission and probably listed building consent as well. An Article 4 direction, most common in conservation areas, can remove permitted development rights altogether, so check before you order. Our guides to solar panels in a conservation area, listed buildings and flats go through each case.
How much solar Cardiff has
The government counted 7,453 solar installations in Cardiff at the end of 2025, up from 5,884 a year earlier, a rise of 27% and about 47 per 1,000 households by our count. That is below the UK average of about 69, and it puts Cardiff 273rd of the 362 UK council areas in the table. The government warns that its 2025 council figures undercount, because many 2025 installations could not yet be matched to a council area, so expect the Cardiff number to be revised upwards.
On the domestic figures for August 2026, the four Cardiff constituencies are close together: Cardiff East 2,254 installations, Cardiff West 2,185, Cardiff South and Penarth 2,120 (which also takes in Penarth, in the Vale of Glamorgan) and Cardiff North 2,021. Across Wales the government reported an 18% rise in solar installations over the previous 12 months, taking the Welsh total to 146,665 by August 2026.
Cardiff's housing: half the Welsh share of detached homes
At the 2021 Census, 14.1% of Cardiff households lived in detached houses against 28.5% across Wales, while 20.2% lived in purpose-built flats against 9.4% for Wales. Another 29.7% were in semi-detached houses and 29.6% in terraced houses. In short, Cardiff has about half the Welsh share of detached homes and more than twice the share of flats, which matters because the Welsh permitted development right for rooftop solar is written for houses.
For a semi or a terrace, the practical questions are roof slope orientation, shading from neighbours and whether the roof covering is sound enough to take panels for 25 years. Our guide to how many solar panels you need helps you size a system to the slope you actually have.
Your network operator in Cardiff
Cardiff sits in National Grid Electricity Distribution's South Wales licence area, formerly Western Power Distribution. A standard home system that is type-tested and under 16A per phase goes down the G98 fit-and-notify route: your installer notifies NGED within 28 days of commissioning, and NGED says the online form takes about 10 to 15 minutes with an instant acknowledgement. Anything larger needs a G99 application, which has to be agreed before the work goes ahead.
Read our G98 and G99 guide for what your installer should be doing on your behalf. You can also compare Cardiff with solar panels in Bristol across the Severn, or with solar panels in Liverpool, which shares its price cap region with North Wales.
Getting solar quotes in Cardiff
Get at least three written quotes from MCS-certified installers, each with a performance estimate for your roof and a full breakdown of what is supplied. That is the Renewable Energy Consumer Code's advice. Never pay more than 25% up front, and walk away from anyone offering a discount to sign on the day. Our guide to choosing a solar installer covers what to check.
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Are solar panels worth it in Cardiff?
For a house with a suitable roof, usually yes. Cardiff generates about 1,029 kWh per kWp a year on the PVGIS model, and every unit you use saves 26.55p at the Southern Wales price cap rate for October to December 2026.
Is there a solar panel grant in Cardiff?
Two Welsh routes. Warm Homes Nest can fit solar for free if you own or privately rent, get a means-tested benefit or have a low income, and your EPC is 54 (E) or less. Green Homes Wales lends £1,000 to £25,000 interest free for solar with no means test, for owner-occupiers whose home is not listed.
Do I need planning permission for solar panels in Cardiff?
Usually not for roof panels on a house, provided they sit below the ridgeline and project no more than 200mm. Flats are not covered by the Welsh permitted development right, conservation areas and World Heritage Sites restrict panels on walls visible from the highway, and listed buildings need consent.
Who is the network operator for solar in Cardiff?
National Grid Electricity Distribution, in its South Wales licence area. A single home system under 16A per phase is notified on G98 within 28 days of commissioning; larger systems need a G99 application agreed first.
Sources for this page
Local sources checked on 16 October 2026. Solar yields: PVGIS 5.2, EU Joint Research Centre, modelled 10 October 2026. Electricity prices: Ofgem price cap by region. System cost and export rate: Energy Saving Trust. Local sources:
- Welsh Government: Nest, free home energy efficiency improvements
- Welsh Government: Nest eligibility
- Development Bank of Wales: Green Homes Wales
- Welsh Government: £5 million more for Green Homes Wales in 2026-27
- Welsh Government: planning permission for solar panels
- Cardiff Council: Tai Clyd Caerdydd
- DESNZ: Renewable electricity by local authority, 2014 to 2025
- DESNZ: Solar photovoltaics deployment (September 2026)
- Nomis: Census 2021 accommodation type (TS044)
- National Grid Electricity Distribution: G98 micro-generation